Diagnostic led

[soxnail]

onehot951
here is a pic with the relevant connect points. The led line goes to the resistor on the klr board. The other side of the led goes to +12v any where on the board. Remember cathode of the led goes to resistor. Anode goes to 12V. Also I am sure you know this but there has to be a suitable resister in the led line to reduce the current so you don't burn out the led.
Sox

[onehot951]

led out referring to the + or RED lead of the LED? as far as the black lead, will any ground work?

[soxnail]

led out is the black lead, NOT the + one. The positive goes to the +12 V.
Sox

[onehot951]

with the cathode being red, does it matter where i get a ground? as far as the resister needed what do you advise and would i still need a resistor if i tapped directly into the diags connector

Jeff

[soxnail]

Ok as Luke (cool hand) would say "what we have here is a failure to communicate".
If your led was connected without a resistor to the diag port then it can be connected to the klr as shown in the picture without a resistor. If you know which is the cathode and which is the anode on the led, then the cathode goes to the resistor on the klr board. The Anode goes to a +12v on the board. Neither of the led leads are connected to ground.
Sox

[onehot951]

i didnt see that movie, but need to look back into what is a cathode and what is an anode as im lost for now.

[soxnail]

Where did you get the led from? did it have any literature with it ? The anode is where the + goes and cathode is where you would ground it. The problem is that the klr uses an active low system to run the led. Thus you connect the + of the led also the anode to the +12V on the klr. The ground or the cathode is connected as shown in the pic. Let me know the details on the led and I can tell you how to hook it up.
Sox

[onehot951]

i purchase the led from radio shack, and its the same part number that lindsey racing said to get for the diags connector led. it has 2 wires coming off of it which radio shack already soldered a red and black wire to. i may have to head back to radio shack if you need the part number but from how it sounds, the led i have needs 3 prongs on it

[soxnail]

Ok I got it now. I thought you were using a basic led. The one you got from radio shack has the right resistor already in it. Also you do not need one with three terminals (there ia no such thing).
The LED you have is constructed as such.


Next
The led has a red wire which is positive and is the anode of the led. The black wire is the negative or ground or the cathode.
To make the led light up it need a 12V differential across it. Like a regular incandescent bulb, but the led is polarity sensitive. (It will only light up with +12V on the red and ground or the negative on the black.
The way the klr drives the led is as follows.
The led is always getting +12V to it from the diagnostic port. The klr grounds the other lead (black) electronically to turn the led on and off, also via the diag port.
When you want to put the led in the car there are two ways that are mostly used. You can run it to the diag port and then get the wires into the car. This means drilling holes and making sure the the said holes do not leak.
The other method is to tie into the klr. This entails opening the klr (as I have done) or opening the klr connector.
I am against opening the klr connector as it is 20 years or so old and wires are brittle in there and can break or short. So opening the klr is the last option. If you are comfortable with a soldering iron and circuit board work then do the following.
1) Open the klr.
2) locate Resistor R502 as shown in the picture solder the black lead to the end of the resistor that is towards the connector side of the klr.
3) Solder the red wire to pin 6 of the klr connector (on the inside of the connector in the klr box).
4) Route the wires out of the klr box. ( I just ran them through the seam in the cover of the klr).
5) Find a spot for your led and you are set.
6) Test the led by taking the TPS connector off while the car is running. It should blink the led.
Hope this helps.
Sox

[onehot951]

id rather remove the klr and do some soldering... im bring my camera to document it incase someone else decides to do this. pics always help

thanks sox

[onehot951]

curious if the connections are te same for an 88 951 vs the 86 951?

Figured i would ask

[onehot951]

Ive come to the conclusion that working on the klr or the dme is kind of like throwing a blank 500.00 check out the window and hoping no one uses it. the curcuit board itself seems pretty durable, but the computer cable that connects to the 2 boards makes one concerned about how many times you can move it before something breaks internally.

[soxnail]

Both 86 and 88 will have the same circuit. The cable can stand quite a few flex unflexes but why push it ? make sure you hold the boards so one does not dangle from the connective cable. You should be fine.
Sox

[onehot951]

trying to solder on the top of the board is creating tolerence problems. SOOO ive gone to the bottom of the board and soldered to post 6. my concern is that down the road, something could cause the insulation to wear through and short something out. Whats your view on this sox?

thank you

[onehot951]

ok i got all the soldering done. i tried it out in the car and it seems to work. i get to remount the dme and klr tomorrow. i did notice that when i disconnect the tps, im getting a 3 flashes....

[soxnail]

As long as you used a high quality thick insulation wire you are ok.
BTW you can get the 12V from somewhere else in the car as opposed to pin 6 and it would also work. Looks like you are all set.
Sox